How to download macOS High Sierra for installing as offline?

[hack3rcon]

Hello,
I have an iMac A1311 and installed macOS Sierra on it and I want to upgrade it to the macOS High Sierra as offline. I downloaded some .dmg file of macOS High Sierra, but when I want to install it, then it tells me "This copy of the Install macOS High Sierra application is damaged, and can‘t be used to install macOS.".
I found this script and it downloaded following files for me:

1. AppleDiagnostics.chunklist
2. AppleDiagnostics.dmg
3. BaseSystem.chunklist
4. BaseSystem.dmg
5. InstallESDDmg.pkg
6. InstallInfo.plist

But, when I clicked on the "Continue" button of the installer, it showed me "The recovery server could not be contacted.". My iMac is connected to the internet and I did:
# ntpdate -u time.apple.com

Any idea to solve it?

Thank you.

 

[amaze1499]

Get gibmacos or SUS inspector from git hub. Download the installer manually.

 

[hack3rcon]

Get gibmacos or SUS inspector from git hub. Download the installer manually.

Hello,
Thank you so much for your reply.
The "This copy of the Install macOS High Sierra application is damaged, and can't be used to install macOS." error was because of the date and time. According to https://discussions.apple.com/thread/251059713?answerId=252006527022#252006527022, I changed it to somewhere between 2015-2017 and problem solved.

 

[amaze1499]

Hello,
Thank you so much for your reply.
The "This copy of the Install macOS High Sierra application is damaged, and can't be used to install macOS." error was because of the date and time. According to https://discussions.apple.com/thread/251059713?answerId=252006527022#252006527022, I changed it to somewhere between 2015-2017 and problem solved.

Good reminder! Cheers!

 

[BrianBaughn]

You can get various macOS installers via the MDS app…

MDS – Twocanoes Software

twocanoes.com

This shows what is currently available: